Sina (SINA+3%) and Youku (YOKU+1.7%) continue their alliance-forming ways by partnering with each other. Youku's videos will be embedded within Sina Weibo (appearing in video search results), and will be pushed to Weibo users through a "personalized recommendation section." The companies talk up the mobile implications of the deal, noting 76% of Weibo daily users access via mobile devices, and that Youku's daily video views have soared to 170M. The deal follows Sina's partnership with Alibaba, Youku's tie-up with Renren, and Baidu's purchase of video site PPS.

Renren (RENN+3.6%) and Youku (YOKU-0.3%) are forming a content partnership, according to a Chinese media report (translation). The deal will reportedly lead to the integration of Youku videos on Renren's social networking platform, and provide additional Renren sharing options for the videos. Renren, which already owns second-tier Chinese video site 56.com, is getting a lift from the news.

Mobile now makes up 15% of Web traffic, up from 10% a year ago, notes Mary Meeker in her latest Internet Trends Report. Also mentioned: China (BIDU, SINA, SOHU, YOKU) has 564M Web users (42% penetration), with 75% accessing the Web from their phones (71% use PCs); India's Web penetration is only at 11% (137M users); mobile now makes up 12% of U.S. media viewing time (it's 22% in China) and 3% of ad spend, up from 10% and 1% before; YouTube's (GOOG) per-minute video uploads are up 5x since '09; 60% of Facebook (FB) users log in daily, and the site receives 350M daily photo uploads; global smartphone penetration is still only at 21%. (Meeker in 2012)

After barely moving yesterday in response to nearly in-line Q1 results and strong Q2 revenue guidance, Youku (YOKU-9.6%) is falling hard today. The decline comes even though Youku has received two upgrades since the report (from HSBC and Maxim), as well as a bullish coverage launch from BofA. Concerns about mobile monetization could be a factor. On its earnings call, Youku stated mobile daily video views rose 50%+ Q/Q and are now above 170M, that mobile monthly users have topped 100M (PC users are around 400M), and that mobile now makes up ~30% of traffic. However, the company added "mobile monetization this year is relatively modest."

Chinese Internet stocks rally following news Alibaba is buying an 18% stake in Sina as it tries to head off competition from Tencent. Youku (YOKU+7%) is the biggest winner, but Baidu (BIDU+2.2%), NetQin (NQ+3.8%), NetEase (NTES+2%), and YY (YY+3.7% - a rival to Tencent's QQ platform) are also having good days. Youku filed its 2012 20-F on Friday.

Sohu (SOHU) and Samsung have reached a deal to have Sohu Video's apps installed on all Samsung phones sold in China over the next 3 years, Shanghai Daily reports. As the paper notes, the deal could give Sohu a boost in its efforts to compete against market leader Youku Tudou (YOKU), which has seen its mobile viewing surge. Strategy Analytics estimates Samsung shipped over 30M smartphones in China last year.

Youku Tudou Inc is an Internet television company in china. Its internet television platform enables consumers to search, view and share high-quality video content quickly and easily across multiple devices.